The case for housing density in the face of climate change

Greer Rasmussen

· Auckland Climathon

Housing density has been a polarising topic in Auckland for a long time. The recent media coverage of and heated debates around Auckland’s Unitary Plan made this polarisation abundantly clear. As housing reaches crisis point in Auckland, we must understand the latent potential that infill or subdivided housing has on improving our affordability, liveability, and environment. Continuing with the status quo of urban sprawl and ever-increasing suburbia will not serve the people of our city or the environment. If incorporated appropriately, increased housing density will improve environmental outcomes for Aucklanders in three key ways: more efficient energy use, better use of land, and improved public transport.

What does “housing density” mean?

Housing density refers to the number of homes in a given area. New Zealand cities are almost entirely made up low density homes - single detached dwellings on individual sections. Low density living housing contributes to urban sprawl. In contrast, high density living describes more people being housed within the current urban footprint. In order to achieve high density housing, existing detached homes must be replaced with more efficient housing such as apartments, townhouses or smaller infill houses. Living closer together creates further efficiencies due to the potential for shared resources such as green spaces, laundry facilities and garages.

High density living and a low carbon footprint: Manhattan, New York

Manhattan is one of the most carbon friendly cities per capita in the developed world. This seems counterintuitive because all the concrete, glass, large buildings and heavy traffic look like an environmental disaster - but this is far from the case. The small average area of its housing, a transport system that favours walking, cycling and public modes of transport, and its highly concentrated land use mean residents generate significantly less carbon than those living in smaller suburban cities and towns.

Transport

Current building plans for Auckland are actually increasing the population’s auto dependency and traffic congestion by establishing housing developments farther from the central city, without providing accessible and reliable public transport options. Cities worldwide such as Los Angeles and Melbourne are adjusting their planning rules and development strategies to encourage transport-centric planning. Transport currently comprises around 20 per cent of NZ’s carbon emissions, most of which is made up of emissions from cars and trucks in urban areas. Higher density living creates a better business case for public transport, cycling and walking investment by councils and the government. Auckland requires a critical mass of people to cover the upfront investment and ensure the ongoing cost of public transport is viable.

Energy efficiency

Apartments, and to a lesser extent, townhouses, are significantly more efficient to heat and cool. A Canadian study showed that on average, apartments were 2.3 times more energy efficient that single detached houses. Shared walls and adjacent units provide natural insulation, which means high density housing inherently offers some efficiency benefits regardless of the building materials used.

Land use

Constraints on land space are driving house prices and urban sprawl in and across Auckland. Every day, our city is growing further south, into Pukekohe and the Waikato, and north, towards Orewa. This spread and conversion of land from rural into suburban has real impacts on climate change and the future liveability of our city. Higher density living will allow us to house Auckland’s growing population without compromising these areas, which are important for food growing, farming, and access to pristine environs. Nature areas, including forests, which exist just outside the city, are especially important for the overall health of our planet: trees are earth’s lungs, breathing in carbon dioxide and breathing out oxygen.

By choosing to live in higher density, energy efficient houses, using public transport that is accessible and reliable, we can protect these vital natural resources. Such lifestyle changes are fundamental if we hope to win the fight against climate change.

Greer Rasmussen is a young urbanist who volunteers with Generation Zero and Women in Urbanism Aotearoa.